A subdomain is a domain that is part of a larger domain; the only domain that is not also a subdomain is the root domain. For example, west.example.com and east.example.com are subdomains of the example.com domain, which in turn is a subdomain of the com top-level domain.

A subdomain is an easy way to create a memorable Web address for unique content areas of your site. For example, you could create a subdomain for pictures on your site called "pics" that is accessible through the URL pics.example.com in addition to www.example.com/pics.

Sub domain is a domain that comes in-front of main domain. Usually its like blog.example.com. Here example is main domain and blog is sub domain. Search engines consider sub domain as an unique website. So we can get more quality back links and traffics from our sub domain.

A subdomain is a second website, with its own unique content, but there is no new domain name. Instead, you use an existing domain name and change the www to another name. The subdomain name looks like forums.domain.com, help.domain.com.

Subdomains are a smaller part of a larger domain.Subdomain names are Web addresses created by adding a third-level domain to your existing domain name. For example, janesbagels.com might have the subdomains shop.janesbagels.com or blog.janesbagels.com.

Sub-domain is the part of the large domain which may contain the content that is bit different from the main site. For example :if domain.com is the main domain name then in blog.domain.com 'blog' is the sub-domain.

Also sub-domain and sub-directory are two different terms. Like domain.com/blog is the sub-directory, where 'blog' is sub-folder within main folder.

Sub-domain is useful to separate out the content that is completely different.This also acts as different website.

Hi,A subdomain is a second website, with its own unique content, but there is no new domain name. It is not always necessary to register a new domain name when the one you already own will work perfectly fine. Rather than registering a new domain name, you can always create a subdomain using a domain you already own.